U.S. patent number 4,131,704 [Application Number 05/646,098] was granted by the patent office on 1978-12-26 for nonwoven fabric comprising needled and selectively fused fine and coarse filaments having differing softening temperatures which is useful as a backing in the production of tufted materials.
This patent grant is currently assigned to Phillips Petroleum Company. Invention is credited to Wayne K. Erickson, John P. Walters.
United States Patent |
4,131,704 |
Erickson , et al. |
December 26, 1978 |
Nonwoven fabric comprising needled and selectively fused fine and
coarse filaments having differing softening temperatures which is
useful as a backing in the production of tufted materials
Abstract
A nonwoven fabric is comprised of a blend of fine staple fibers
and coarse staple fibers randomly oriented with the fine staple
fibers having a higher melt flow than the coarse staple fibers. In
the manufacture of the nonwoven fabric, same is needled whereby the
needles select the fine fibers and portions of same are positioned
in a plane generally transverse to the plane of the fabric.
Infrared heat is used to fuse the fine fibers at overlapping
portions thereof to provide integrity for the fabric. The coarse
staple fibers are held in the interstices of the fabric at least
partially by frictional engagement with the fine staple fibers.
Inventors: |
Erickson; Wayne K. (Greenville,
SC), Walters; John P. (Greenville, SC) |
Assignee: |
Phillips Petroleum Company
(Bartlesville, OK)
|
Family
ID: |
24591742 |
Appl.
No.: |
05/646,098 |
Filed: |
January 2, 1976 |
Current U.S.
Class: |
428/95; 28/112;
442/407 |
Current CPC
Class: |
D04H
1/48 (20130101); D05C 17/02 (20130101); Y10T
428/23979 (20150401); Y10T 442/688 (20150401) |
Current International
Class: |
D05C
17/02 (20060101); D05C 17/00 (20060101); D04H
1/48 (20060101); B32B 005/06 (); B32B 005/08 ();
B32B 005/12 (); D04H 001/48 () |
Field of
Search: |
;428/300,95,296,297,300,301,303,288 ;28/72.2R |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Cannon; J.C.
Claims
What is claimed and descired to be secured by Letters Patent
is:
1. A tufted pile fabric comprising:
(a) a primary backing of fine staple fibers and coarse staple
fibers including:
(1) 75 to 25 percent by weight of said fine staple fibers of
polypropylene having a lower softening temperature than that of
said coarse fibers, thereby permitting the selective fusing of fine
staple fibers in preference to fusing of coarse staple fibers, said
fine staple fibers being randomly oriented in the plane of the
backing, said fine staple fibers having portions thereof extending
in a direction generally transverse to the plane of the backing,
overlapping portions of said fine staple fibers being selectively
fused together to provide integrity for the fabric.
(2) 25 to 75 percent by weight of coarse staple fibers of
polypropylene having a denier at least twice that of the fine
fibers, said coarse staple fibers being randomly oriented and
intermixed with the fine staple fibers, and coarse staple fibers
being in a plane substantially parallel to the plane of the backing
and being retained in the interstices of the fine staple fibers by
frictional engagement with the fine staple fibers with a major
portion of the length of the coarse staple fibers being free of
fusion bonding to thereby allow said coarse staple fibers to move
within said interstices; and
(b) tufted yarns piercing said primary backing; and
(c) a secondary backing adhered to said tufted primary backing.
2. The fabric as set forth in claim 1 wherein portions of said fine
fibers overlap portions of said coarse fibers and certain of these
overlapping portions are bonded together.
3. A nonwoven fabric comprised of a plurality of different types of
staple fibers, said fabric including:
(a) 75 to 25 percent by weight of fine staple fiber of synthetic
material randomly oriented in the plane of the fabric with said
fine staple fibers having portions thereof extending in a direction
generally transverse to the plane of the fabric, overlapping
portions of said fine staple fibers being selectively fused
together to provide integrity for the fabric;
(b) 25 to 75 percent by weight of coarse staple fibers having a
denier of at least twice that of the fine staple fibers, of
synthetic material having a higher softening temperature than the
softening temperature of the fine staple fibers, thereby permitting
the selective fusing of fine staple fibers to fine staple fibers in
preference to fusing of coarse staple fibers, said coarse staple
fibers being randomly oriented in the plane of the fabric and
intermixed with the fine staple fibers, said coarse staple fibers
being positioned in a plane substantially parallel to the plane of
the fabric and being at least partially retained in the interstices
of the fine staple fibers by frictional engagement with the fine
staple fibers, said coarse staple fibers have a major portion of
their length free of fusion bonding to thereby allow said coarse
staple fibers to move within said interstices.
4. The fabric as set forth in claim 3 wherein portions of said fine
fibers overlap portions of said coarse fibers and certain of these
overlapping portions are bonded together.
5. The fabric as set forth in claim 3 wherein said fine fiber has a
melt flow of at least about 10 units above that of said coarse
fibers and both coarse and fine fibers are polypropylene.
6. The fabric as set forth in claim 5 wherein said fine fibers have
a length in the range of about 11/2 inches to about 5 inches and
said coarse fibers have a length in the range of about 5 inches to
about 8 inches.
7. A nonwoven fabric comprised of a plurality of different types of
staple fibers, said fabric including:
(a) 75 to 25 percent by weight of fine staple fibers of synthetic
material randomly oriented with said fine staple fibers having
portions thereof extending in a direction generally transverse to
the plane of the fabric, overlapping portions of said fine staple
fibers being fused together, said fine staple fibers having a
length of about 4 inches;
(b) 25 to 75 percent by weight of coarse staple fibers having a
denier of at least twice that of the fine staple fibers, of
synthetic material having a lower melt flow than the melt flow of
the fine staple fibers with said coarse staple fibers being
randomly oriented and intermixed with the fine staple fibers, said
coarse staple fibers being oriented in a plane substantially
parallel to the plane of the fabric and being at least partially
retained in the interstices of the fine staple fibers by frictional
engagement with the fine staple fibers, said coarse staple fibers
having a length of about 6 inches, said fine staple fibers having a
melt flow of at least about 10 units above that of said coarse
staple fibers as measured by ASTM D1238-65T condition L, thereby
permitting selective fusing of fine staple fibers to fine staple
fibers in preference to fusing of coarse staple fibers, the
synthetic material of the fine staple fibers and the synthetic
material of the coarse staple fibers being polypropylene.
8. A method of making a nonwoven fabric, said method including the
steps of:
(a) forming a web of intermixed and randomly oriented fibers of
which 75 to 25 percent is fine staple fibers of synthetic material
and 25 to 75 weight percent is coarse staple fibers of synthetic
material having a denier of at least about twice that of the fine
fibers, said coarse fibers having a higher softening temperature
than that of the fine fibers;
(b) needling said web with needles having a barb size sufficiently
small for selectively needling the fine fibers in preferance to the
coarse fibers whereby portions of the fine fibers extend in a
direction generally transverse to the plane of the fabric and said
coarse fibers are generally parallel to the plane of the fabric;
and
(c) heating the needled web to a temperature sufficient to
selectively bond the fine fibers together at overlapping portions
thereof in preference to bonding the coarse fibers, with the
majority of the length of the coarse fibers being free of fusion
bonding and movable within the interstices of the fine fibers and
held therein by friction.
9. The method as set forth in claim 8 wherein portions of said fine
fibers overlap portions of said coarse fibers and certain of these
overlapping portions are bonded together.
10. The method as set forth in claim 8 wherein said fine fibers
have a melt flow of at least about 10 units above that of said
coarse fibers and both fibers are polypropylene.
Description
New uses are being developed for nonwoven fabrics, a major use of
which is as a primary and/or secondary backing for a carpet.
Traditionally, jute has been used as a backing material for carpets
but because of the lack of reliability in the supply of jute,
substitutes have had to be developed. It has been found that
nonwoven fabric can be used successfully but some of these fabrics
have had a tendency toward excessive shrinkage during carpet
manufacture and failure of the backing to retain the tufted pile
secured to the backing because of fiber breakage. In the use of
nonwoven fabrics for carpet backing, the integrity of the fabric is
normally maintained by fusing or bonding portions of the fibers
together. Tufting the pile in such a backing to form a carpet
requires excessive tufting force because the fibers are less
capable of moving relative to one another to allow the tufting to
be inserted through the carpet backing. This also leads to
excessive tufting noise plus weakening of the carpet backing.
The principal objects and advantages of the present invention are:
to provide a nonwoven fabric which is useable as a carpet backing
or the like which overcomes the above-mentioned difficulties; to
provide such a fabric which is easy to manufacture with currently
available equipment requiring a minimum of equipment modification;
to provide such a fabric which is well adapted for its intended
use; and to provide a method of manufacturing a non-woven fabric
wherein the produced fabric requires reduced needling force for
tufting.
Other objects and advantages of the present invention will become
apparent from the following description taken in connection with
the accompanying drawings wherein are set forth by way of
illustration and example certain embodiments of the present
invention.
FIG. 1 is a top view of a nonwoven fabric shown magnified
approximately 50.times..
FIG. 2 is a bottom view of the fabric shown in FIG. 1 magnified
approximately the same amount.
FIG. 3 is an edge view of the fabric shown in FIGS. 1 and 2 and is
magnified approximately 50.times..
FIG. 4 is an edge view of the fabric as used to form a carpet
backing and having pile inserted therein.
FIG. 5 is a plan view of an apparatus used to produce a nonwoven
fabric.
As required, detailed embodiments of the present invention are
disclosed herein, however, it is to be understood that the
disclosed embodiments are merely exemplary of the invention which
may be embodied in various forms. Therefore, specific structural
and functional details disclosed herein are not to be interpreted
as limiting but merely as a basis for the claims and as a
representative basis for teaching one skilled in the art to
variously employ the present invention in virtually any appropriate
detailed structure.
The reference numeral 1 designates generally a nonwoven fabric
comprised of a blend of fine staple fibers and coarse staple
fibers, both of which are randomly oriented within the network of
the fabric 1. The fibers are of a synthetic material such as
polypropylene and copolymers thereof, with the coarse fibers being
of a denier at least twice the denier of the fine fibers. The use
of the word "denier" herein is interpreted to mean fiber denier
value is based on the assumption that the materials of the fibers
have the same density. In other words, denier is used as a measure
of the relative cross-sectional areas of the particular fibers. The
fine fibers are selectively needled instead of the coarse fibers
whereby portions of the fine fibers extend generally transverse to
the plane of the fabric as can be seen in FIG. 3 with the fine
fibers being those that are darker. Also, the fine fibers are fused
at overlapping portions thereof to provide integrity for the
nonwoven fabric.
The material of the coarse fibers can be of the same material or
the fine fiber can be of one material and the coarse fiber can be
of another material to help provide for the selective fusing or
bonding of the fine fibers. To accomplish this, the fine fibers
have a higher melt flow than the coarse fibers. This difference
should be at least 10 melt flow units as measured by ASTM D1238-65T
condition L. This, then, means that the fine fibers have a lower
softening temperature whereby same will fuse or bond together in
preference to bonding or fusing of the coarse fibers. However,
proper selection of the fusing temperature will allow a certain
limited amount of fusing and/or mechanical bonding between the fine
fiber and the coarse fiber when the fabric is produced by the
method described below. However, the majority of the length of the
coarse fibers is unfused to the fine fibers and thereby allows the
coarse fibers to move within the interstices of the fabric. The
coarse fibers are also held within the interstices of the fabric by
frictional engagement with fine fibers and other coarse fibers.
The coarse fibers are preferably of a longer length than the fine
fibers as for example, about 5 to 8 inches and preferably 6 to 7
inches (15 cm.) or longer, while the fine fibers are about 11/2 to
5 inches and preferably 3 to 4 inches (10 cm.). The use of long
fibers provides more strength for the fabric and also results in a
fabric having decreased elongation and the use of the fine fibers
in connection with the coarse fibers provides for better cover with
less material fibers when the nonwoven fabric is in use as for
example as a primary or secondary carpet backing.
As described above, when needling of the nonwoven fabric during
manufacture, a proper selection of barb size on the needles results
in selection of the fine fibers in preference to the coarse fibers
wherein certain portions of the fine fibers extend generally
transverse to the plane of the fabric to help provide integrity for
same after fusing. By proper selection of the coarse fiber
cross-sectional area, same will not be selected by the needles
during needling wherein same will lie in a plane substantially
parallel to the plane of the fabric. Because of the selective
fusion by the proper selection of melt flows for the respective
fibers, the coarse fibers are relatively free to move within the
interstices of the fabric which when the fabric is used, as for
example for a carpet backing, the tufting force can be reduced.
Four fabrics having substantially the same weight of fibers were
made and the tufting force measured is shown in the following
table:
______________________________________ Needle Force Fibers Used
Melt Method Required for in Fabric Polymer Flow** of Fusion Tufting
______________________________________ 3 DPF-4 in. poly- 20
Infrared 4-4.5 lbs (10 cm.) propylene heat fused (1.80-2.025 kg) 3
DPF-4 in. poly- 20 Roll fused 3-3.5 lbs (10 cm.) propylene
(1.35-1.575 kg) 12 DPF-6 in. poly- 8 Infrared 1-1.5 lbs* (15 cm.)
propylene heat fused (.45-.675 kg) 3 DPF-4 in. poly- 20 (10 cm.)
propylene 12 DPF-6 in. poly- 8 (15 cm.) propylene (A blend of
Infrared 2 lbs (.90 kg) 50% of each heat fused of the above fibers)
______________________________________ *Cover and distribution were
poor for the 12 DPF fabric. The other fabric exhibited adequate
cover. **ASTM D1238-65T Condition L.
The above table shows that fabric produced according to the
teaching of the present invention provides a fabric which requires
reduced needling force while still providing good cover and fiber
distribution within the fabric. The blend should have between 25
percent and 75 percent by weight of fine staple fiber and 75 to 25
percent by weight of the coarse staple fiber in the blend of fibers
used to produce the above-described fabric.
The above-described fabric can be produced on substantially
conventional equipment used to make nonwoven fabric such as the
apparatus shown in FIG. 5. It is to be understood that
modifications or additions to the equipment described can be
provided and still produce the above-described fabric. As shown,
the reference numeral 5 designates generally an apparatus for
producing nonwoven fabric wherein feed means 6 such as bale
breakers, blender boxes, feed boxes, etc., feed fibers in the form
of staple to a breaker carding machine 7. Carded webs 8 of fibers
proceed to crosslappers 9 to form intermediate bats. These
intermediate bats are then passed to a finisher carder 10 to
produce carded webs which are then picked up by crosslappers 11.
The above-described elements are well known in the art of
manufacturing nonwoven fabrics. The carded webs are then fed onto
lapper aprons 12 wherein the fibers are then dispersed on a floor
apron 13. As shown, two of the above-described portions of the
apparatus 5 are provided to make a thicker web from which a
nonwoven fabric is made. However, one or any other suitable number
of the above-described portions of the apparatus 5 can be provided.
The web passes from along the floor apron 13 to nip rollers 15
wherein the web is drafted in the machine or warp direction and
then the web is passed to a needler 16. The needler then needles
the web and by proper selection of a needle barb size the fine
fibers are selected in preference to the coarse fibers wherein
portions of the fine fibers are needled through the fabric wherein
portions of the fine fibers are generally transversed to the plane
of the fabric as described above. After exiting the needler 16, the
web passes through further nip rollers 17 for more machine
direction drafting of the web. The drafted web after exiting the
nip roller 17 then passes to a tenter frame 18 for drafting of the
web in a direction transverse to the machine direction. While
passing along the tenter frame, and while being maintained in a
stretched condition, the web is subjected to infrared heat from an
infrared heater 19 to effect the fusing or bonding of the fine
fibers to one another and occasionally to the coarse fibers as is
described above. From the tenter frame the fused fabric is cooled
and the trim and the edges are trimmed after which the fabric is
removed from the apparatus by take-up means 20. The above described
portions of the apparatus 5 are well known in the art of fabric
manufacturing and details of same are therefore not disclosed in
detail herein.
The fabric as disclosed above is useful as a primary or secondary
carpet backing and as such same can be processed in conventional
carpet manufacturing apparatus for tufting the fabric with yarn or
fabric as is known in the art. By having the coarse fibers of the
above-described fabric relatively free to move within the
interstices of the fabric the coarse fibers can move out of the way
of the tufting needles and thereby reduce the amount of force
required to effect the tufting. Because of the slight amount of
bonding of the coarse fibers to the fine fibers, same are retained
within the interstices of the fabric to help retain the tufted yarn
on the carpet backing. The tufts 23 can be of any suitable type
such as that used in carpets having loop or cut piles or any other
type known in the art. As seen in FIG. 4, a typical carpet
construction would be comprised of a primary layer 25 of fabric 1
tufted yarn 23 extending therethrough, a latex coating 24, and a
secondary layer 26 of fabric 1 adhered to the latex.
It is to be understood that while we have illustrated and described
certain forms of our invention, it is not to be limited to the
specific form or arrangement of parts herein described and
shown.
* * * * *